The present invention provides a method of and materials for optically printing highly conductive images.
Most techniques for the deposition of high electrical conductivity lines or characters involve the depositing of metals onto a substrate, or by direct printing using highly conducting metallic dispersions in a suitable vehicle. Other methods used include thermal decomposition of organometallic compounds and electrochemical deposition.
More recently considerable interest has been directed towards highly conducting organic "charge transfer" compounds. In particular, emphasis has been placed on low ionization potential organic donors and their charge transfer salts formed by oxidation with organic acceptors such as 7,7,8,8, tetracyanoquinodimethane (TCNQ).
The most conducting organics known are the 1:1 TCNQ salts of the fulvalene-type donor compounds such as tetrathiafulvalene (TTF), tetraselenafulvalene (TSeF), cis/transdiselenadithiafulvalene (DSeDTF) and cis/trans dimethyl tetrathiafulvalene (ATTF). The composition (TTF) (TCNQ), for example, shows a conductivity .sigma.(RT) = 500(.OMEGA.-cm).sup.-.sup.1 at room temperature. The isomorphic selenium analog, (TSeF) (TCNQ), the subject of commonly assigned patent application Ser. No. 477,553, shows an even larger metallic conductivity, e.g., .sigma..apprxeq.800(.OMEGA.-cm).sup.-.sup.1 at room temperature.
In this regard see British Pat. No. 1,382,748, U.S. Pat. No. 3,252,061, U.S. Pat. No. 3,781,281, U.S. Pat. No. 3,799,814, U.S. Pat. No. 3,162,641, publications to L. Russell Melby, entitled "Substituted Quinodimethans", Canadian Journal of Chemistry, Vol,43 (1965), to L. Russell Melby et al., entitled "Substituted Quinodimethans II", J. Amer. Chem, Soc., vol. 84 (1960); to F. Wudl et al., entitled "Electrical Conductivity by the Bis, 1,3-dithiole-Bis-1,3 dithiolium System", J. Amer. Chem. Soc., Vol. 94.2 (Jan. 26, 1972); to F. Wudl et al., entitled "Bis-1,3-ditholium Chloride: An Unusually Stable Organic Radical Cation", Chemical Communications, p.1453 (1970); to Jerome H. Perlstein et al., entitled "Electron Transport and Magnetic Properties of New Highly Conducting TCNQ Complexes", AIP Conference Proceedings, No. 10, part 2 (1972).